Diabetes is a disorder affecting large numbers of people worldwide. Management approaches to control Type I and Type II diabetes aim primarily at normalizing blood glucose levels to prevent short- and long-term complications. Many patients require multiple daily injections of an insulin to control their diabetes. Several insulin products have been produced that control blood sugar levels over differing time intervals. Several products combine various forms of insulin in an attempt to provide a preparation which controls glucose levels over a wider period of time.
Previous attempts to normalize blood glucose levels in Type I and Type II diabetic patients have centered on the subcutaneous administration of insulin in various time-released formulations, such as ultralente and humulin NPH insulin pharmaceutical products. These formulations have attempted to delay and subsequently control the bio-distribution of insulin by regulating release of insulin to peripheral tissues with the expectation that sustained management of insulin bioavailability will lead to better glucose control. Glargine insulin is a long-acting form of insulin in which insulin is released from the subcutaneous tissue around the site of injection into the bloodstream at a relatively constant rate throughout the day. Although glargine insulin is released at a constant rate throughout the day, the released insulin reaches a wide range of systems within the body rather than being delivered to targeted areas of the body. What is needed is a composition of insulin where a portion of the dosed insulin is released at a relatively constant rate throughout the day and another portion of insulin that is time released from the site of administration and targeted for delivery to the liver to better control glucose production.
There is, therefore, an unmet need in the art for compositions and methods of managing blood glucose levels in Type I and Type II diabetic patients. The present invention meets these needs by providing a long-acting composition comprising insulin that is free and insulin that is associated with a lipid construct targeted for delivery to hepatocytes. A lipid construct is a lipid/phospholipid particle in which individual lipid molecules cooperatively interact to create a bipolar lipid membrane which encloses and isolates a portion of the medium in which it was formed. The lipid construct releases free insulin over time as well as targets a portion of the remaining insulin to the hepatocytes in the liver to better control glucose storage and production.